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trbochrgd1
08-25-2004, 11:13 AM
I have a 82 grand prix with a LC2 motor in it. I am getting 12 pounds of vacuum at idle. The gauge is pretty steady on 12. I have a comp cam with a .425 lift intake and .425 exhaust/206 intake and 206 exhaust duration at .050 . Car leaves great lifts the front wheel off the ground. But then dies out I have to pedal the car down the track. Anyone got any ideas? Thanks.

Keller
08-25-2004, 05:35 PM
What is your fuel pump setup and where are you picking up your fuel from? You may be down on fuel capacity or pumping some air while accelerating.

trbochrgd1
08-25-2004, 08:59 PM
I have a aeromotive in-line pump with an 8 gallon fuel cell in the trunk. 72# injectors. pt61 turbo. dfi.

Keller
08-25-2004, 11:17 PM
With a DFI, I assume you are running no MAF, right?

It could be just about anything. Fuel starvation, over-rich condition, crank or cam trigger electrical problem...plus just about any fuel or spark mapping anomaly with the DFI. I know in the early days, people would go therough tankfulls of gas just trying to get a car to idle right. Fel-Pro and other more modern units have improved things greatly.

Does your DFI data show anything?

trbochrgd1
08-26-2004, 10:27 AM
I have the car tuned by Turbo People in New York. I have the program, but I really let him do all the tuning. I got the dfi back in 1998. It's not the easiest to work with, I know. Come to think of it my last pass in the car the fuel pressure gauge went crazy and pegged to 90 psi and then went back to around 45 psi. Maybe my fuel pressure regulator is going? I will put another fuel gauge on the rail and check for fuel pressure tonight. I spoke to Job jr. (who tunes the car and he said it sound like weak valve springs, or something mechanical but I will cover all my bases before I condem anything. Do you have any thing on adjusting the cam sensor? I am going crazy trying to look for somthing, just can't find it. Because that would cause a low vacuum condition too correct? (If 12 pounds of vacuum at idle is low)Thank you for your help! I appreciate it.

Michael

Keller
08-26-2004, 12:10 PM
Whoa...90 to 45...that's a quite a swing. Something is _way_ wrong if things are moving around that much. If your base pressure is ~45 or so, the pressure should only be at 90 if you were running 45 PSI boost, which I doubt. Maybe you do have your regulator locking up? Or an insufficient return line for that fuel pump?

See http://www.gnttype.org/techarea/ecmsensors/ecmpage.html There are several articles on setting / adjusting the cam sensor.

trbochrgd1
08-26-2004, 02:19 PM
Yeah,that is a big swing in pressure. It just started to happen, and I have had this problem that last few times I have taken the car out so maybe the regulator is finally letting go. I will definetly check the pressure tonight. Thanks for the link.

trbochrgd1
08-26-2004, 09:45 PM
So, I just checked the fuel pressure with a gauge hooked up to the fuel rail. It read 75 psi. That could be the problem. I guess something is hanging up in the regulator. I tapped it and tried to readjust it. I got it back down to about 40 psi. I will order a new one tomorrow. Even engine vacuum went up to 14-15 psi.